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Konjac Glucomannan in Food Manufacturing for Solubility, Viscosity, Synergy and Gelling

Konjac Glucomannan (KGM) is a natural food gum extracted from the hemicellulose component in the cell walls of Amorphophallus konjac plants. These plants are native to Southeast Asia, where they have been used as a food source for thousands of years.


Glucomannan is a polysaccharide consisting of the monosaccharide glucose and mannose.

Konjac Glucomannan carries European food numbers : E 425, E 425(i) and E 425(ii) and is approved by the FDA for food use.

    • E 425 is unrefined Konjac tuber and has a marine flavour (it’s sometimes described as somewhat fishy). It can be 30-45% glucomannan with Viscosity of ≥ 12,000 mpa.s.
    • E 425(i) is refined Konjac to ≥ 65% glucomannan with a Viscosity of ≥ 22,000 mpa.s and can be produced near odourless.
    • E 425(ii) (KGM) is ≥ 95 glucomannan with a Viscosity of ≥ 36,000 mpa.s. Up to 40,000.  Kāpiti Health Foods KGM E425(ii) is the developed version of E 425(i), and has higher requirements on Glucomannan content and lower SO2 (to under 10 Parts per million) and is odourless.

1. Solubility and Konjac

  • The large molecular weight lowers the solubility of Glucomannan in water, but the presence of a large number of hydroxyl groups in the molecule enables it to absorb around 80-100 times.

2. Viscosity of Konjac Glucomannan

  • Depending on the percentage of glucomannan present, 1g KGM dissolved in 100g water can achieve viscosity of up to 40,000 mPa⋅s, which is the highest viscosity among gums at the same concentration, such as xanthan and Arabic gum.
  • Compared with thickeners such as guar gum, xanthan gum, and locust bean gum, konjac is a nonionic polysaccharide and is less affected by salt ions (calcium, potassium, or sodium ions) in viscosity and gel structure
.
  • The high viscosity enables it to be used as a thickening agent in sauces, soups, and dressings.

3. Synergy of Konjac Glucomannan and Other Hydrocolloids in Food Manufacturing

  • Carrageenan and Konjac Glucomannan Gum structure analysis shows good synergistic effects between k-Carrageenan and konjac glucomannan. It forms within the kappa carrageenan network a structure with cross linking of konjac gum through the intermolecular hydrogen bonds. When w (carrageenan): w (KGM) is 5.5:4.5, the result reaches maximum gel hardness with high shear strength.
    • When the proportion of KGM in the mix is further increased, adhesiveness and elasticity is increased.
  • Xanthan Gum and Konjac Glucomannan Gum are non gel polysaccharides, Konjac-xanthan gels are cohesive and extremely elastic in nature. Max gel strength is seen at a ratio of konjac and xanthan between 0.7 to 0.3 at 1% concentration.
  • Locust Bean Gum and Konjac Glucomannan Gum solutions do not gelatinise. But they can form gel in combination with Carrageenan. The solution synergy can be improved significantly with the help of Locust Bean Gum.
  • Guar Gum and Konjac Glucomannan Gum have good synergy due to their similar molecular structure. The blend can produce a powerful film, which can be used, for example, as a preservation film on fruits and vegetables.

4. Konjac Glucomannan as a Gelling Agent

  • Konjac Glucomannan can be used to produce a thermally irreversible gel
. This property is used to produce calorie-free noodles like shirataki, tofu, rice, and puddings. The flavour present in the hydrating process can be encapsulated into these kinds of konjac based foods
.
  • Thermally reversible gel can be formed when heating solution combinations of konjac with xanthan gum, gellan gum, carrageenan, and other hydrocolloids.

Next Application of Konjac Glucomannan (KGM) in Food Manufacturing

For detailed information about the application of Konjac in your food manufacturing process and to obtain samples, contact us.